1,4-bis-styryl-benzene-dioxyalkanoic acids,salts and esters

ABSTRACT

The present invention relates to new bis-stilbene compounds of the formula   WHEREIN R1 and R2 are identical or different and denote alkyl with five to 18 carbon atoms, substituted alkyl with a total of two to 20 carbon atoms, or alkenyl with three to four carbon atoms, X1 and X2 are identical or different and denote hydrogen, alkoxy with one to four carbon atoms, halogen, alkenyl with three to four carbon atoms or alkyl with one to four carbon atoms, Y1 and Y2 are identical or different and denote hydrogen, halogen, alkenyl with three to four carbon atoms or alkyl with one to four carbon atoms, a represents hydrogen, halogen, alkoxy with one to four carbon atoms or alkyl with one to four carbon atoms, and the parapositions are free of alkoxy groups or R1O- and R2O- groups.

United States Patent 1191 1111 3,843,718

Luethi 1 Oct. 22,1974

[5 1,4-BlS-STYRYL-BENZENE- 1,247,934 9 1-971 Great Britain DIOXYALKANOIC ACIDS, SALTS AND 1576913 France ESTERS OTHER PUBLICATIONS [75] Inventor: Christian Luethi, Muenchenstein, Hell Chem- Abstw 571 13390 g,

Switzerland [73] Assignee: Giba-Geigy AG, Basle, Switzerland Primary Emmin'er L0m1lne Wainberger Assistant Exammer-John F. Terapane [22] Filed: 11 1972 Attorney, Agent, or Firm.loseph G. Kolodny; Edward 21 APPL 230 931 McC. Roberts; Prabodh l. Almaula [30] Foreign Application Priority Data ABSTRACT May 3, 1971 Switzerland 3235/71 The present invention relates to new bis-stilbene com- Febv 3, 1972 Switzerland 1608/72 pounds of the formula Y1 Y2 X1 X2 2% @1-1=0H @H=OH l R10 0R2 a a 8 [52] U.S. Cl. ...260/473 G, 117/335 T, 252/3012 W, wherein R and R are identical or different and de- 260/465 F, 260/512 R, 260/512 C, 260/520, note alkyl with five to 18 carbon atoms, substituted 260/544 M, 260/559 B, 260/600, 260/606.5 alkyl with a total of two to 20 carbon atoms, or alke- P, 260/613 R, 260/951 nyl with three to four carbon atoms, X and X are [51] Int. Cl. C070 69/76 identical or different and denote hydrogen, alkoxy [58] Field of Search 260/520, 473 G with one to four carbon atoms, halogen, alkenyl with three to four carbon atoms or alkyl with one to four carbon atoms, Y and Y are identical or different and [56] References Cited denote hydrogen, halogen, alkenyl with three to four UMTED STATES PATENTS carbon atoms or alkyl with one to four carbon atoms. 3,755,446 8/1973 Scheuermann @1111. 260/473 R a represents hydrogen halogen alkoxy one to four carbon atoms or alkyl with one to four carbon atoms, and the parapositions are free of alkoxy groups FOREIGN PATENTS OR APPLICATIONS 1 Or and gmups- 1,576,018 6/1969 France 3 Claims, No Drawings 1,4-BIS-STXRXLQENZEljE-DIOXYALKANOIC wherein R denotes alkyl with to 18 carbon atoms, al-

ACIDS, SALTS AND ESTERS kenyl with 3 to 4 carbon atoms or a substituted alkyl The new compounds are useful as optical brightengroup with a total of 2 to 12 carbon atoms, of which the ers. substituents can be phenyl, phenyl substituted by lower The present invention relates to new bis-stilbene 5 alkyl or halogen, carboxyl, including its salts, carbalkcompounds, their use as optical brighteners, and prooxy or carbophenoxy, carbonamido with an optionally cesses for their manufacture. substituted amido group, the sulpho group including its French related Specification 1,576,018 already dis salts, nitrile, halogen, hydroxyl or alkoxy and wherein closes bis-stilbene compounds of relates structure and furthermore X represents hydrogen, alkoxy with l to their usability as optical brighteners. Asafurther devel- 4 carbon atoms, halogen, alkenyl with 3 to 4 carbon opment of these investigations, some selected types of atoms or alkyl with l to 4 carbon atoms, Y represents compound have now been discovered which, because hydrogen or halogen, alkenyl with 3 to 4 carbon atoms of special substitution characteristics, display particuo lkyl ith 1 t0 4 carbon atoms and wherein the paralarly advantageous properties, above all for certain Positions are free of alkoxy g p 2 g p fi ld f b. Compounds of the formula Ya a Xi Xi 0H=CH@@ CH=GH WMVM The new compounds according to the present invenwherein R denotes alkenyl with 3 to 4 carbon atoms tion generally correspond to the formula or a substituted alkyl group with a total of 2 to 8 carbon Y1 Y2 X1 2 R 0 1 OR:

' .7 i m to a a.

atoms, whereof the substituents can bephenyl, phenyl substituted by lower alkyl or halogen, carboxyl includingits salts, carbalkoxy, carbonamido with an optionwherein R and R are identical or different and denote alkyl with 5 to 18 carbon atoms, substituted alkyl with a total of 2 to 20 carbon atoms, or alkenyl with 3 to 4 carbon atoms, X and X are identical or different and ally substituted amido group, the sulpho group includdenote hydrogen, alkoxy with l to 4 carbon atoms, haling its salts, nitrile, halogen, hydr'oxyl or alkoxy and ogen, alkenyl with 3 to 4 carbon atoms or alkyl withl 40 wherein furthermore X, represents hydrogen, alkoxy to 4 carbon atoms, Y and Y areidentical or different with 1 to 4 carbon atoms or alkyl with l to 4 carbon and denote hydrogemhalogen, alkenyl with 3 to4caratoms and Y represents hydrogen or halogen, and hen atoms or alkyl with l to 4 carbon atoms, a reprewherein the para-positions are free of alkoxy groups or sents hydrogen, halogen, alkoxy with 1 to 4 carbon R O groups.

atoms or alkyl with l to 4 carbon atorns and the parac. Compounds of the formula positions are free of alkoxy groups or R O- and R O- wherein the substituents R,O- occupy the positions 2 groups. or 3 and wherein R denotes carboxyl with '2 to 12 car- Preferred groups of compounds within the framebon atoms or its alkali, ammonium and amine salts, N- work of the formula( 1 can be defined by the formulae monoand N,N-di-( hydroxyalkyl)-carbonamidoalkyl (2) to (5) listed below: with 4 to 8 carabon atoms, sulphonic acid alkyl with 2 a. Compounds of the formula to 4 carbon atoms or its alkali, ammonium and amine Y r Xi l X! salts, X represents hydrogen, alkoxy with l to4carbon cept of the carbonamido group and its substitution atoms, chlorine, bromine, alkenyl with 3 to 4 carbon products it should be noted that this is to be understood atoms or alkyl with l to 4 carbon atoms, Y represents to include both the CO-NH group and its monohydrogen, chlorine, bromine, alkenyl with 3 to 4 carsubstitution and di-substitution products, and of course bon atoms or alkyl with l to 4 carbon atoms and i cyclic amide derivatives (morpholino, piperidino and wherein the para-positions are free of alkoxy groups or t like) are also to b6 regarded as ded. Though R,O groups. alkylamide derivatives (including substituted alkyld. Compounds of the formula amide derivatives such as hydroxyalkyl-, cyanoalkyl-,

wherein the substituents R O- occupy the positions 2 carboxyalkyl-, carbalkoxyalkyland halogenoalkylor 3 and wherein R denotes carboxyalkyl with 2 to 12 amide derivatives) are of predominant interest and carbon atoms or its alkali salts, carbalkoxyalkyl with up here normally the number of carbon atoms is up to 18, to 18 carbon atoms, sulphoalkyl with 2 to 3 carbon it is not intended to exclude different amide derivaatoms (as the alkali salt or free acid), benzyl, which tives. may be substituted by chlorine or by alkyl groups con- 20 The bis-stilbene compounds of the formula 1) and taining 1 to 4 carbon atoms, or alkenyl with 3 to 4 carof the subsidiary formulae can be manufactured analobon atoms, X; represents hydrogen or alkoxy with 1 to gously to methods which are in themselves known. Ex- 4 carbon atoms and the para-positions are free of alkplaining this for the example of compounds of the foroxy groups or R O groups, mula 2), the procedure followed is, for example, that e. Compounds of the formula about 1 mol equivalent of a compound of the formula wherein R denotes alkyl with 5 to 12 carbon atoms, al- (7) kenyl with 3. to 4 carbon atoms, halogenoalkyl, cyanoalkyl or alkoxyalkyl with 2 to 6 carbon atoms, benzyl, a a or benzyl substituted by chlorine or methyl, carboxyaly to 12 carbon atoms or alkah ammomum is reacted with about 1 mol equivalent of a compound and amine salts, carbalkoxyalkyl with 2 to 10 carbon f the f l atoms, carbophenoxyalkyl with 1 to 3 carbon atoms in the alkyl part and phenyl optionally substituted by 40 X Y1 methyl, carbonamidoalkyl with 2 to 4 carbon atoms, N-monoand N,N-di-( hydroxyalkyl)- carbonamidoalkyl with 4 to 8 carbon atoms, N-monoand N,N-di-( alkyl)-carbonamidoalkyl with 2 to 10 carbon atoms which can Optionally be Substituted by and about one mol equivalent of a compound of the dialkyl( l to 3 carbon atoms)-amino groups, N-phenylformula carbonamidoalkyl with 1 to 3 carbon atoms in the alkyl part and optionally with chlorine as a substituent in the Y2 Y phenyl radical, sulphonic acid alkyl with 2 to 4 carbon atoms or, its alkali, ammonium or amine salts, and X Zr represents hydrogen, chlorine, bromine, methoxy, alkyl with l to 4 carbon atoms or alkenyl with 3 to 4 carbon atoms, and the para-positions are free of methoxy groups or R O groups.

In these formulae 3) to 6) it should be noted generally that unless more detailed comments are made with one of the symbols Z and Z denoting a O=CH- group and the other denoting one of the groupings of the formulae the preferred halogen is chlorine, alkyl is to be un- 0 O derstood as both straight-chain and branched alkyl, -oH,-1 -o-R, CH;-i O-R preferably with a non-branched carbon atom in the 0 a-position to the ether bridge and, in the case of substi- (10) (11) tuted alkyl groups, the number of carbon atoms of the alkyl part is normally 1 to 18, preferably 1 to 4. f f Amongst possible alkenyl groups as provided, for exand ample, for R the allyl group is preferred and it l t amongst lower alkyl groups those with l to 4 carbon 12 13 atoms are always to be understood, unless otherwise stated. Possible salts of carboxyl groups and sulpho wherein R represents an alkyl radical which is optiongroups are above all the alkali, alkaline earth, ammoally substituted further, preferably an alkyl radical with nium and amine salts. By way of explanation of the conup to 6 carbon atoms, an aryl radical, preferably a phe-' group) is to be excluded.

with mammalian Emiibdfi of the formula nyl radical, a cycloalkyl radical, preferably a cyclohexyl radical or an aralkyl radical, preferably a benzyl radical.

In the abovementioned formulae, the symbols X X Y and Y have the meaning given earlier. R, and R 5 have the meaning given for R and R under the formulae (2) and f 3), with the restriction that the meaning of modified carboxyl groups (carbalkoxy, carbophenoxy and optionally substituted carbonamide The modification of the carboxyl groups is effected after condensation of the compounds (8) or 9) with the diphenyl component, by'convertingcompounds according to the formulae 2) or 3) or subsidiary formulae, having free carboxyl groups, or their alkali salts, into corresponding acid halides and manufacturing the corresponding esters or amides therefrom in accordance with methods which are in themselves known.

In accordance with the reaction principle explained above, it is possible, for example, to react dialdehydes of the formula withbifunetional compounds the formula wherein V denotes one of the phosphorus-containing substituents of the formulae (10), (ll), (12) or 13).

The phosphorus compounds of the formulae (15), l6) and 19) here required as starting substances are obtained in a manner which is in itself known by react- Halogen-C Hz CHg-IIBIOE6I1 with phosphorus compounds of the formulae In these formulae, R has the indicated meaning, with radicals R bonded to oxygen being preferably lower alkyl groups whilst radicals R directlybonded to phosphorus are preferably aryl radicals such as benzene radicals. The phosphorus compound of the formula 12) can also be obtained by reaction of halogenomethyl compounds, preferably chloromethyl or bromomethyl compounds of the formulae 20), 21) or (22), with chlorodiphenylphosphine and subsequent reaction with an alcohol of the formula R-OI-l (the meaning of R being as defined above), for example with methanol or with water.

l EXAMPLE To manufacture compounds according to the formula (2) it is possible to use, in particular, those of the abovementioned process variants according to which about 1 mol equivalent of a compound of theformula is reacted with about one mol equivalent each of a compound of the formula I I7) and 18), with 2, denoting a grouping of the formulae (10),(1 l l2) and l3).

A variant of particular practical importance is to use, as the diphenyl components accordingto the formula 19), those which correspond to the formula wherein R denotes an alkyl group with l to 6carbon atoms.

The manufacturing process is advantageously carried out in inert solvents. As examples thereof, there may be i mentioned hydrocarbons such as toluene and xylene or alcohols such as methanol, ethanol, isopropanol, butanol, glycols, glycol-ethers such as Z-methoxyethanol, hexanols, cyclohexanol and cycloo'ctanol, and also ethers such as diisopropyl ether, tetrahydrofurane and dioxane, as well as dimethylsulphoxide, formamide and N-methylpyrrolidone. Polar organic solvents such as dimethylformamide and dimethylsulphoxide are particularly suitable. Some of the reactions can also be carried out in aqueous solution.

The temperature at which the reaction is carried out can vary within wide limits. It is determined a) by the inertness of the solvent used towards the reactants, es pecially towards the strongly basic alkali compounds, B) by the reactivity of the condensation partners and 'y) by the activity of the combination of solvent and base as a condensation agent.

In practice, accordingly, temperatures between about and 100C are in general used, especially if dimethylformamide or dimethylsulphoxide are em ployed as solvents. The preferred temperature range is to 60C. However, under certain circumstances higher temperatures can also be employed if this is desired for reasons of time saving or if a less active but cheaper condensation agent is to be employed. In principle, reaction temperatures in the range of 10 to 180C are thus also possible.

Strongly basic alkali compounds which can be used are above all the hydroxides, amides and alcoholates (preferably those of primary alcohols containing 1 to 4 carbon atoms) of the alkali metals, amongst which those of lithium, sodium and potassium are, for economic reasons, of predominant interest. In principle, and in special cases, it is however also possible to employ successfully alkali sulphides and alkali carbonates, arylalkali compounds, such as, for example, phenyllithium, or strongly basic amines (including ammonium bases, for example trialkylammonium hydroxides).

When using the processes described above for the manufacture of asymmetrical derivatives (which are of lesser importance), the competing reaction of the three reactants in the first place yields mixtures of asymmetrically substituted bis-stilbene compounds according to the formula (2) and the two corresponding symmetrically substituted bis-stilbenes. The separation of these components, if desired, is effected by fractional recrystallisation, column chromatography and/or utilisation of the different behaviour of certain groups (for example carboxylic acid groups and sulphonic acid groups) towards certain reagents (for example aqueous alkaline solutions). a

The aldehydes which are circumscribed, for example, by the formulae l7) and 18), are not all known, but the manufacture of a large number is described in the literature (see, for example, Ann. 401, page 91 to 1 19 (1913); J. Pr. Ch. 77, page 364 to 366 1908); Ber. 38, page 1676 1905); DR? 209,608; Ann. 357, page 313 to 383 (1907); J. Med. Chem. 12, page 420 to 424 1969)). They are obtained almost without exception by etherification of the corresponding hydroxybenzaldehydes. Hitherto unknown aldehydes are also obtainable by analogous processes. The section dealing with examples deals especially with the manufacture of some aldehydes.

Within the framework of the present invention, preferred practical significance attaches to the reaction according to the formulae 17) to 19) of aldehydes of the formulae 01 0110 CHO OH0 Rw R'wo o1 dR'w CHO QOHO on, 0Rw Rwo Rw wherein R denotes a lower alkyl group and R represents an allyl, benzyl, acetic acid, propionic acid, butyric acid, propylenesulphonic acid or alkyl group with 8 to 1 8 carbon atoms, with 4,4 -dialkoxyphosphonomethyl)-di-phenyl, or the compounds according to the formula (3) obtained there from, with carboxyl groups being appropriately esterified or amidised, if desired.

The new compounds defined above show a more or less pronounced fluorescence in the dissolved or finely divided state. They can be used for'the optical brightening of the most diverse synthetic, semi-synthetic or natural organic materials or substances which contain such organic materials.

The following groups of organic materials, to the extent that an optical brightening thereof is relevant, may be mentioned as examples of such materials, without the list which follows being intended to express any restriction thereto:

1. Synthetic organic high molecular materials:

a. Polymerisation products based on organic compounds containing at least one polymerisable carboncarbon double bond, that is to say their homopolymers or copolymers as well as their after-treatment products such as, for example, crosslinking, grafting or degradation products, polymer blends, products obtained'by modification of reactive groups, for example polymers based on afi unsaturated carboxylic acids or derivatives of such carboxylic acids, especially on acrylic compounds (such as, for example, acrylic esters, acrylic acid, acrylonitrile, acrylamides and their derivatives or their methacryl analogues) on olefine hydrocarbons (such as, for example, ethylene, propylene, styrenes or dienes, and also so-called ABS polymers), and polymers based on vinyl and vinylidene compounds (such as, for example, vinyl chloride, vinyl alcohol and vinylidene chloride);

b. Polymerisation products which are obtainable by ring opening, for example, polyamides of the polycaprolactam type, and also polymers which are obtainable both via polyaddition and via polycondensation, such as polyethers or polyacetals;

c. Polycondensation products or precondensates based on bifunctional or polyfunctional compounds possessing condensable groups, their homocondensation and co-condensation products, and aftertreatment products, such as, for example, polyesters,

especially saturated (for example ethylene glycol terd. Polyaddition products such as polyurethanes (crosslinked and non-crosslinked) and epoxide resins.

Semi-synthetic organic materials, for example, cellulose esters of varying degrees of esterification socalled 2 z-acetate or triacetate) or cellulose ethers, regenerated cellulose (viscose or cuprammonium cellulose), or their after-treatment products, and casein plastics.

III. Natural organic materials of animal or vegetable origin, for example based on cellulose or proteins, such as cotton, wool, linen, silk,v natural lacquer resins, starch and casein.

The organic materials to be optically brightened can be in the mostdiverse states of processing raw materials, semi-finished goods or finished goods). On the other hand, they can be in the form of structures of the most diverse shapes, that is to say, for example, predominantly threedimensional bodies such as sheets, profiles, injection mouldings, various machined articles, chips, granules or foams, and also as predominantly two-dimensional bodies such as films, foils, lacque'rs, coverings, impregnations and coatings, or as predominantly onedimensional bodies such as filaments, fibres, flocks and wires. The said materials can, on the other hand, also be in an unshaped state, in the most diverse homogeneous or inhomogeneous forms of division, such as, for example, in the form of powders, solutions, emulsions, dispersions, latices, pastes or waxes.

Fibre materials can, for example, be in the form of endless filaments (stretched or unstretched), staple fibres, flocks, hanks, textile filaments, yarns, threads, fibre fleeces, felts, waddings, flock structures or woven textile fabrics or textile laminates,-knitted fabrics and paper, cardboards or paper pulps.

The compounds to be used according to the invention are of importance, inter alia, for the treatment of organic textile materials, especially woven textile fabrics. Where fibres, which can be in the form of staple fibres or endless filaments or in the form of hanks, woven fabrics, knitted fabrics, fleeces, flock substrates or laminates, are to be optically brightened according to the invention, this is advantageously effectedin an aqueous medium, wherein the compounds in question are present in a finely divided form, (suspensions, socalled micro-dispersions or possibly solutions). If de sired, dispersing agents, stabilisers, wetting agents and further auxiliaries can be added during the treatment.

Depending on the type of brightener compound used, it may prove advantageous to carry out the treatment in a neutral or alkaline or acid bath. The treatment is usually carried out at temperatures of about to I 140C, for example at the boiling point of the bath or near it (about 90C). Solutions or emulsions in organic solvents can also be used for the finishing, according to the invention, of textile substrates, as is practised in the dyeing trade in so-called solvent dyeing padthermofix application, or exhaustion dyeing processes in dyeing machines).

The new optical brighteners according to the present invention can further be added to, or incorporated in, the materials before or during their shaping. Thus they can for example be added to the compression moulding composition or injection moulding composition during Powdering onto polymer chips or granules for spinning compositions,

Bath dyeing of polymer chips or granules for spinning compositions,

Metered addition to spinning melts or spinning solutions, and

Application to the tow before stretching.

The new optical brighteners according to the present invention can, for example, also be employed in the following use forms: v

a. Mixed with dyestuffs (shading) or pigments coloured pigments or especially, for example, white pigments), or as an additive to dye baths, printing pastes, discharge pastes or reserve pastes, or for the aftertreatment of dyeings, prints or discharge prints.

b. Mixed with so-called carriers, wetting agents, plasticisers, swelling agents, anti-oxidants, light protection agents, heat stabilisers and chemical bleaching agents chlorite bleaches or bleaching bath additives).

0. Mixed with cross-linking agents or finishes (for example starchor synthetic finishes), and in combination with the most diverse textile finishing processes, especially synthetic resin finishes (for example creaseproof finishes such as wash-and-wear,' permanent-press" or no-iron, as well as flameproof finishes, soft handle finishes, anti-soiling finishes or anti-static finishes, or antimicrobial finishes.

d. Incorporation of the optical brighteners into polymeric carriers (polymerisation, polycondensation or poly-addition products), in a dissolved or dispersed form, for use, for example, in coating compositions, impregnating compositions or binders (solutions, dispersions and emulsions) for textiles, fleeces, paper and leather.

e. As additives to so-called master batches.

f. As additives to the most diverse industrial products in order to render these more marketable (for example improving the appearance of soaps, detergents and pigments.

g. In combination with other optically brightening substances.

h. In spinning bath preparations, that is to say as additives to spinning baths such as are used for improving the slip for the further processing of synthetic fibres, or from a special bath before the stretching of the fibre.

i. As scintillators for various purposes of a photographic nature, such as, for example, for electrophotographic reproduction or supersensitisation and for the optical brightening of photographic layers, optionally in combination with white pigments, such as for example TiO If the brightening process is combined with textile treatment methods or finishing methods, the combined treatment can in many cases advantageously be carried out with the aid of appropriate stable preparations, which Contain the optically brightening compounds in such concentration that the desired brightening effect is achieved. i

In certain cases, the brighteners are made fully effective by an after-treatment. This can, for example, represent a chemical treatment (for example acid treatment), a thermal treatment (for example heat) or a combined chemical/thermal treatment. Thus, for example, the appropriate procedure to follow in optically brightening a series of fibre substrates, for example of polyester fibres, with the brighteners according to the invention is to impregnate these fibres with the aqueous dispersions (optionally also solutions) of the brighteners at temperatures below 75C, for example at room temperature, and to subject them to a dry heat treatment at temperatures above 100C, it being generally advisable additionally to dry the fibre material beforewith dry, superheated steam. The drying and dry heat treatment can also be carried out in immediate succession or be combined in a single process stage.

The amount of the new optical brighteners to be used according to the invention, relative to the material to be optically brightened, can vary within the wide limits. A distinct and durable effect is already achievable with very small amounts, in certain cases, for example, amounts of 0.0001 per cent by weight. However, amounts of up to about 0.8'per cent by weight and optionally up to about 2 per cent by weight can also be employed. For most practical purposes, amounts between 0.0005 and 0.5 per cent by weight are of preferred interest.

The new optical brighteners are'also suitable for use as additives for wash baths or to industrial detergents and domestic detergents, and can be added in various ways. They are appropriately added to wash baths in the form of their solutions in water or in organic solvents, or in a finely divided form as aqueous dispersions. They are advantageously added to domestic detergents or industrial detergents in any stage of the process of manufacture of the detergent, for example the so-called slurry before spray-drying the detergent powder, or during the preparation of liquid detergent combinations. They can be added both in the form of a solution or dispersion in water or other solvents and without auxiliaries, as a dry brightener powder. The brighteners can for example be mixed, kneaded or ground with the detergent substances and mixed in this form into the finished washing powder. They can however also be sprayed as a solution or pre-dispersion 991.91% fi ished d e en Possible detergents are the known mixtures of washactive substances such as, for example, soap in the form of chips and powders, synthetic detergents, soluble salts of sulphonic acid half-esters of higher fatty alcohols, arylsulphonic acids with higher and/or multiple alkyl substituents, sulphocarboxylic acid esters of medium to higher alcohols, fatty acid acylaminoalkylor -aminoar-ylglycerinesulphonates, phosphoric acid esters of fatty alcohols and the like. Socalled builders which can be used are, for example, alkali polyphosfor example: Antistatic agents, agents which protect the skin and restore fats, such as lanoline, enzymes, anti-microbial agents, perfumes and dyestuffs.

The new optical brighteners have the particular advantage that they are active even in the presence of active chlorine donors, such as, for example, hypochlorite, and can be used without significant loss of the effects in wash baths containing non-ionic detergents, for example alkylphenol-polyglycol-ethers.

The compounds according to the invention are added in amounts of 0.005 to 1 percent or more, relative to the weight of the liquid or pulverulent, finished detergent. Wash liquors which contain the indicated amounts of the optical brighteners claimed, impart a brilliant appearance in daylight when used for washing textiles of cellulose fibres, polyamide fibres, cellulose fibres with a high quality finish, polyester fibres, wool and the like.

The wash treatment is carried out, for example, as

follows:

at 20 to 100C in a wash bath which contains 1 to 10 g/kg of a snythetic composite detergent and 0.05 to 1 percent of the brighteners claimed, relative to the weight of the detergent. The liquor ratio can be 1:3 to 1:50. After washing, the textiles are rinsed and dried in the usual manner. The wash bath can contain 0.2 g/l of active chlorine (for example as hypochlorite) or 0.1 to 2 g/l of sodium perborate, as a bleaching additive.

In the examples parts, unless otherwise stated, are always parts by weight, and percentages always percentages by weight. Unless otherwise stated, the melting points and boiling points are uncorrected.

Manufacture of some benzaldehyde ethers (starting products) The instructions below serve as examples of the manufacture of new aldehydes used in the subsequent examples. A. 43.6 g of commercial sodium hydride (about 55 percent strength) are suspended in 800 ml of (anhydrous) dimethylformamide. 152 g of o-vanillin, diluted with 200 ml of dimethylformamide, are added dropwise over the course of 30 minutes at 20 to 25C whilst cooling and the mixture is stirred for a further 3 hours at 20 to 25C. 168 g of bromoacetic acid methyl ester are then run in over the course of half an hour whilst cooling and the mixture is thereafter stirred for a further 18 hours at 20 to 25C. After it has been poured out onto ice/water and the precipitate has been filtered off and rinsed with water, the product is dried V in vacuo at 30 to 40C. 188 g of the aldehyde of the formula CHO (35) -oHo can be manufactured by employing propanesultone in the reaction instead of a bromine compound.

B. 29 g of sodium methylate are suspended in 400 ml of anhydrous dimethylformamide. A solution of 76 g of benzylbromide are mixed in and the mixture is kept at to C for 20 hours, C for 30 minutes and to C for 30 minutes. 2,500 ml. of water are then added followed by 50 ml of glacial :acetic acid, and the oil is extracted with chloroform. After distilling off the solvent, the residue is fractionated, whereupon 76.5 g of Z-benzyloxy-3-methoxybenza1dehyde pass over at boiling point 214 to 215C.

C, 183 g of m-Hydroxybenzaldehyde and 182 g of allyl bromide in 500 ml of absolute alcohol are kept under reflux for 5 hours in the presence of 210 g of potassium carbonate. The filtrate is freed of the alcohol on a rotary evaporator and is fractionally distilled. 3-m- Allyloxybenzaldehyde passes over at boiling point mm 133 to 134C (176 g) Further aldehydes manufactured according to Example A:

Melting Point Boiling Point 1C) t(C) pfmm) 2-n-Octoxybenzaldehyde 194-6 12 Z-Carbomethoxymethoxybenzaldehyd'e 54-5 3-Carbomethoxymethoxybenzaldehyde 31-3 133-6 0.15 Sodium salt of 2-sulphopropoxybenzaldehyde Decomposition 3-n-Octoxybenza1dehyde 204-9 17 3-Carboxymethoxybenzaldehyde 1 14-6 Sodium salt of 3-su1phopropoxybenzaldehyde Decomposition Z-Carboxymethoxybenzaldehyde 129-31 2-n-Octadecyloxy-S-methoxybenzaIdehyde 63-4 Sodium salt of 2-su1phopropoxy-3-methoxybenza1dehyde -7 2-1Z-Ethyl-hexyloxy)-benzaldehyde 174-6 1 l 3-n-Pentoxy-X-alkylbenzaldehyde (Note 1) 132-8 0.05 2-14-Bromo-n-butoxy)benzaldehyde 154-5 1 1 2-( 3Cyano-n-propoxy)benzaldehyde 50-1 2-13-Carboxy-n-propoxy)benzaldehyde 89-91 2-( 3-Carbethoxy-n-propoxy)benzaldehyde 128-30 0.14 2-n-Dodecy1oxy-3-alkylbenzaldehyde 176-95 0.2 Sodium salt of 2-su1phopropoxy-3,S-dimethylbenzaldehyde Decomposition Z-Carboxymethoxy-3-methyl-5-tertvbutylbenzaldehyde 150-3 0.05 Z-Carbomethoxymethoxy-3-methy1-5-tert.butylbenzaldehyde 133-7 0.05 2-Dodecyloxy-3,5-dich1orobenza1dehyde 178-84 0115 2-Carboxymethoxy-3,S-dichlorobenzaldehyde 167-9 2-Carbomethoxymethoxy-3,S-dichlorobenzaldehyde 1 17-8 Sodium sa)1t of 2-sulphopropoxy-X-crotyl-benzaldehyde Decomposition (note 1 Further aldehydes manufactured according to Example 13:

Melting Point Boiling Point 1C) t(C) plmm) 3-Benzy1oxybenzaldehyde 56-7 Z-Benzyloxybenzaldehyde 205-6 1 1 2-Benzy1oxy-3-allylbenzaldehyde 197-208 1 1 2-Benzyloxy-3-methyl-5-tert.butylbenza1dehyde 153-4 0.05 2-Benzy1oxy-3.S-dichlorobenzaldehyde 82-3 3-14-Methylbenzyloxy)-benzaldehyde 142-5 0.03 2-( 3-Chlorobenzy|oxy)-benza1dehyde 43-5 Z-Benzy1oxy-X-croty1-benza1dehyde (Note 1) 133-49 0.03

Further aldehydes manufactured according to Example C and according to methods from Liebigs Annalen, Vol. 401, pages 91 to 119 (1913)v Melting Point Boiling Point 1C) t1C) p(mrn) 2'Allyloxybenzaldehyde 136-7 I3 2-Hydroxy-3-allylbenzaldehyde 2-A11y1o'xy-3-methoxybenzaldehyde 152-5 12 3-Hydroxy-X-allylbenzaldehyde (Note 1) 169-73 14 2-Crotyloxybenzaldehyde 85-6 0.04 g-Hydroxy-x-crotylbenzaldehyde [Note 1) -5 12 llyloxy-S-bromobenzaldehyde The allyl rearrangement led to two different allyl isomers (presumably in the 2-and 4-position) which were employed as a mixture in the reaction to give the distyrylbiphenyl derivatives claimed.

Similarly, the 2-crotyl ether gave a mixture of, presumably 3-and S-crotyl isomers, which were also furlati on and is liquid at room temperature, was also 615- tained analogously to this example.

EXAMPLE 1 13.9 g of sodium methylate are suspended in 120 ml of anhydrous dimethylformamide. A solution of 18 g of OCHeCOOH b t 3 ml of dimet liylforrnamide 5nd 7 M 4 100 ml of water and the solution is run into 300 ml of 2 N hydrochloric acid whilst stirring. The product which has precipitated is filtered off, dried and recrystallised from dimethylformamide-toluene. 12.1 g of the compound of the formula are obtained. Melting point: 263 to 267C decomposition).

EXAMPLE 3 7 g of the free acid of the formula 37) in 75 ml of toluene and 12 ml of thionyl chloride, with the addition of 0.1 ml of dimethylformamide, are reacted for 5 hours at 70C. The mixture is diluted with 350 ml of toluene and filtered at the boil, and the compound which crystallises out from the filtrate is filtered off. 6.9 g of the compound of the formula 1 ocmo are thus obtained. Melting point: 197 to 199C.

EXAMPLE 4 The acid chloride of the formula 38) can be converted into corresponding esters of amides by reaction B-'(2-formylphenoxy)-acetic acid and 20 g of 4,4-biswith alcohols, phenols or primary/secondary amines or dimethoxyphosphonomethyl)-diphenyl in 80 ml of anammonia in accordance with known methods. If, for example, it is reacted for 4 hours under reflux with twice the calculated amount of diethanolamine in dioxane, the product of the formula stirred for a further 3 hours at 40 to C, a further 200 ml of dimethylformamide are then added and just sufficient water is introduced at C to give a clear solution. The precipitate formed after cooling is filis obtained after recrystallisation from dioxane-water. On passing ammonia into a solution of the acid chloride in chlorobenzene at 1 10C and filtering off the precipitate formed, the unsubstituted amide CH=CH CH=CH- t ered off, rinsed with water and dried. 24.3 g of the compound of the formula OCH; 0

obtained.

The following method of manufacture is suitable for of melting point 300C are obtained.

EXAMPLE 2 The compound (36) from Example 1 can be converted into the free acid as follows: 18.3 g are dissolved amides and esters of carboxyalkyl-ethers of the bisstilbenes described here:

The corresponding acid chloride is dissolvedin a small excess of a non-polar anhydrous solvent such as tstrashhwqtbane-to n rq l asen or Xylene the solution is cooled to room temperature, a two fold $(CHz)7-CIT;

- rnethylate suspension at 20 to 40C. The mixture is then stirred for a further 3 hours at 45C. The reaction mixture is poured out into 1,000 ml of 0.5 N hydrochloric acid, the whole is briefly heated to the boil and gradually cooled to room temperature, and the solid is filtered off. The filter cake is dispersed in 1,000 ml of water whilst still moist, treated with 500 ml of acetone and heated for 1 hour under reflux. After cooling to 20 to 22C, the product is filtered off and rinsed with water.

53.4 g of the product of the formula filtered off in an analytically pure form after cooling to which after two recrystallisations from dimethylformto C.

amide melts at 240 to 242C, are thus obtained.

Distyryl-biphenyl derivatives of the present invention, whereof the starting aldehydes do not possess any salt-forming groups, are obtainable analogously but with half the amount of sodium methylate.

If instead of sodium methylate, potassium methylate is employed and the mixture is poured out into water instead of into hydrochloric acid, the compound of the ,formula 42) is obtained in the form of its potassium salt.

EXAMPLE 5 14.5 g of sodium methylate (97 percent pure) are suspended in 60 ml of anhydrous dimethylformamide. 47.0 g of m-octoxybenzaldehyde and 40 g of 4,4'-bis- (dimethoxyphosphonomethyl)-diphenyl are dissolved in 175 ml of dimethylformamide at 70C and this solution, whilst still warm, is added dropwise over the course of about 15 minutes to the above sodium methylate suspension at 20 to 40C. The mixture is then stirred for a further 2 /2 hours at 40 to 45C. 175 ml of water are added, the mixture is neutralised with glacial acetic acid, heated to refluxing and cooled to 0 to 5C, and the product which has precipitated is filtered off. After drying and recrystallisation from nonane, 24 g of the compound of the formula EXAMPLE 7 15.7 g of potassium tert.-butylate are suspended in 100 ml of anhydrous dimethylformamide; 8.1 g of mallyl-oxybenzaldehyde, 8.1 g of o-allyloxybenzaldehyde and 22.7 g of 4,4-bis-(diethoxy-phosphonomethyl)- diphenyl are dissolved in 100 ml of dimethylforniarnide at 75C and this solution, whilst still warm, is added dropwise over the course of about 20 minutes to the above otassium tert.-butylate sus ension at 20 to EXAMPLE 6 v C. T he mixture is then stirred to a further 4 hours 27.8 g of sodium methylate (97 percent strength) are at 40C and poured out into 750 ml of water, and the suspended in 80 ml of anhydrous dimethylsulphoxide. material which gradually solidifies is filtered off. For 36 g of o-(carboxypropyloxy)-benzaldehyde and 40 g purification, the dried crude product is dissolved in exof 4,4-bis-( dimethoxyphosphonomethyl)-diphenyl are cess chlorobenzene, the solution is treated with 1 g of dissolved in 200 ml of dimethylsulphoxide at 70C and. fullers earth, the filtrate is concentrated until a precipithis solution, whilst still warm, is added dropwise over tate appears and is then cooled to 0 to 5C, and the the course of about 30 minutes to'the above sodium product is filtered off and rinsed with'petroleum ether.

A mixture of the three compounds are obtained. Melting point: 182 to 183C.

is thus obtained. This mixture shows advantages, in the shade of brightening and in the solubility in plastics such as polyethylene, overthe individual symmetrical compounds 43) and (45).

enorah-o of a compound which is assumed to correspond to the formula EXAMPLE 8 1 1.7g of sodium methylate (97 percent strength) are H suspended in 50 ml of di'methylsulphoxide. 41.2 g of 2- 4-bromobutoxy)-benzaldehyde and 37.2 g of 4,4-bis- (diethoxyphosphonomethyl)-diphenyl are dissolved in 150 ml of dimethylsulphoxide at 70C and this solution and of a compound of the presumed formula CHqCH; CH=CH Br- (CH -(L are obtained. Since all three compounds show similar properties, the mixture can be employed, without separation, for brightening organic materials.

The examples listed in Table 1 below can be manufactured in accordance with one of the methods described earlier (see note in last column).

The following text presents, by way of examples, a series of possible uses of the class of compounds claimed, without thereby intending to impose a restricis added dropwise to the above suspension over the course of about 30 minutes at 20 to 250C. The whole tion; compounds with copolymerisable or cois then stirred for a further 4 hours at 30 to 35C. The condensable groups, such as allyl, carboxyl or carbalkreaction mixture is then poured into 750 ml of wateroxy can, if the addition to the organic material to be and stirred in an ice bath until the precipitated product brightened is carried out appropriately, become copohas solidified, and this product is filtered off, washed v lymerised or co-condensed and thereby more resistant with water and dried in a vacuum cabinet at C. 52 to migration.

NE. R1 R2 3 R4 R5 1 Can be manufactured according to example number.

Bleached cotton fabric is washed for 30 minutes, using a liquor ratio of 1:30, in a liquor heated to 60C,

EXAMPLE 9 whichcontains the following additives per litre: 0.032 g of the brightener of the formula (36) l g of active chlorine (bleach solution) 4 g of a washing powder of the following composition:

7.00 percent of sodium metasilicate 2.00 percent of carboxymethylcellulose and 0.25 percent of ethylenediaminetetraacetic acid.

After rinsing and drying, the fabric shows a strong brightening effect of good fastness to acid and tochlorine.

The washing powder of the abovementioned composition can also contain the brightener of the formu (36) incorporated directly.

A strong brightening effect is also achieved if the washing process is carried out for 30 minutes at 20C.

Similar results are obtained with the compounds of the formulae (37), (64), (65), (66) or-(86).

v EXAMPLE Cut pieces of polyamide 6, bleached wool and Koratron, finished cotton are together treated for 10 minutes at 30C, using a liquor ratio of 1:20 in a bath which contains 0.1' percent of the brightener of the formula 37), calculated relative to the fibre material, and 0.5 g/l of sodium fluosilicate.

After rinsing and drying, the three fibre materials show a strong brightening effect of good fastness to light.

Similar results are obtained when using the compounds of the formulae (36), (66), (86) or (96).

EXAMPLE 1 l A cotton article provided with a non-iron finish by means of an aminoplast resin is washed for minutes, using a liquor ratio of 1:20, in a liquor warmed to 50C which contains the following additives per litre:

0.004 to 0.016 g of a brightener of the formula (36),

4 g of a washing powder of the following composition:

EXAMPLE 12 Brightening of cotton fabric in a rinsing bath containing an agent for imparting a soft handle: Stock solution: 0.05 g of the compounds of the formula Y (88) is dissolved in 5 ml of a mixture of alcohol and dimethylformamide 1:1) and'added to ml of a 4 percent strength aqueous solution of di-( octadecyl)- dimethyl-ammonium chloride.

Bleached cotton fabric is rinsed for 10 minutes at 20 to C, using a liquor ratio of 1:20, in an aqueous liquor which contains 5 percent of the above stock solution, and is subsequently dried at 80C. The fabric is strongly brightened, without a greenish tinge.

The compounds of the formulae (36), (37), (41), (67), (68), (69), (80), (86), (87), (88), (89) or (93) give similar effects.

EXAMPLE 13 A polyamide fibre fabric Perlon Helanca) is washed for 15 minutes, using a liquor ratio of 1:20 in a liquor warmed to C which contains the following additives per litre:

0.004 to 0.016 g of the brightener of the formula 66),

0.25 g of active chlorine (bleach solution) 4 g of a washing powder of the following composition:

15.00 percent of dodecylbenzenesulphonate 10.00 percent of sodium laurylsulphonate 40.00 percent of sodium tripolyphosphate 25.75 percent of anhydrous sodium sulphate 7.00 percent of sodium metasilicate 2.00 percent of carboxymethylcellulose and 0.25 percent of ethylenediaminetetraacetic acid. The polyamide fibre fabric is only introduced into the wash bath, warmed to 50C, 15 minutes after preparation of the latter. After rinsing and drying, the fabric shows a good brightening effect of good fastness to light.

A good brightening effect is also obtained if the washing process is carried out in the same manner, but at 25C.

The washing powder of the abovementioned composition can also contain the brightener of the formulae indicated above incorporated directly.

Similar results are obtained when using the compounds of the following formulae: (36), (37), (52), (62), (64), (65), (67), (82), (86) or (97).

EXAMPLE l4 Polyacrylonitrile fibres (Orlon 42 or Courtelle) are introduced, using a liquor ratio of 1:40, into an aqueous bath which per litre contains 1 g of percent strength formic acid and 0.2 percent of the compound of the formula (96), calculated relative to the fibre weight. The treatment bath is heated to the boil over the course of 30 minutes and is kept at this temperature for a further 30 to 60 minutes. After rinsing and drying, polyacrylonitrile fibres showing an excellent brightening effect are obtained.

Good brightening effects are also obtained if Courtelle fibres are treated in accordance with this example.

EXAMPLE 15 A polyamide fibre fabric Perlon) is introduced, using a liquor ratio of 1:40, into a bath at 60C which contains 0.1- percent (relative to the weight of fabric) of the brightener of the formula 97) and also contains, per litre, l g of 80 percent strength acetic acid and 0.25 g of an addition product of 30 to 35 mols of ethylene oxide to one mol of technical stearyl alcohol. The mixture is warmed to the boil over the course of 30 minutes and kept at the boil for 30 minutes. After rinsing and drying, a strong brightening effect of good fastness to light is obtained.

If instead of the polyamide-6 fabric a polyamide-6,6 (Nylon) fabric is used, similar good brightening effects are obtained.

Finally, the treatment can be carried out under HT- conditions, for example for 30 minutes at 130C. For this type of use, it is advisable to add 3 g/l of hydrosulphite to the liquor.

Similar results are obtained with the compounds of the formulae (36), (37), (43), (45), (52), (53), (54), (56), (57), (62) to (67), (73), (82), (86) and (92).

EXAMPLE l6 Polypropylene fibres or polyethylene fibres are treated, using a liquor ratio of 1:40, with 0.02 to 0.4 percent of the compound of the formula 68), (73) or (82) for 60 minutes, at 60 to C, in a bath which per litre contains 5 g of an addition product of about 35 mols of ethylene oxide to 1 mol of octadecyl alcohol and 0.5 g of trisodium phosphate. The material is then rinsed and dried. The polyolefine fibres thus obtained possess a substantially higher degree of whiteness than the untreated fibres.

If instead of 0.5 g of trisodium phosphate 1 g of 85 percent strength formic acid is used, a similar effect is obtained.

Example 17 A cellulose acetate fabric is introduced, using a liquor ratio of 1:30 to 1:40, into an aqueous bath at 50C which contains 0.15 percent of the bis-stilbene compound of the formula (36), relative to the fibre material. The temperature of the treatment bath is brought to 90 to 95C and maintained thereat for to minutes. After rinsing and drying, a good brightening effect is obtained.

Similar effects are achieved with the compounds of the formula (37), (64), (89), (96) or (97).

EXAMPLE 18 Bleached wool fabric is treated, using a liquor ratio of 1:40, for 60 minutes in a bath which contains 0.1 to 0.4 percent of the brightener of the formulae (66), 86) or (96), calculated relative to the fibre weight, and 4 g/l of hydrosulphide. After rinsing and drying, strong brightening effects of goodfastness to light are obtained.

Strong brightening effects are also obtained if instead of the hydrosulphite 5 percent of acetic acid, calculated relative to the fibre weight, are added to the bath.

EXAMPLE 19 A nylon-6 fabric is impregnated with the following liquor at room temperature on a padder, and squeezed out to a weight increase of 140 percent: 5 g/l of the brightener of the formula (41 (43), (45), (57), (62), (73), (91 (92), (94), or (97), 5 g/l of lactic acid and 20 g/l of the reaction product of 1 mol of diethanolamine to coconut fatty acid, made up to=l litre with perchloroethylene. The brightener is worked into a paste with the surface-active agent and the lactic acid and is then added to the organic solvent.

Following the padding and drying, the fabric is steamed for 3 minutes at C.

The substrate shows a good brightening effect.

Instead of the steaming process, the fabric can also be thermofixed for 30 seconds at C.

EXAMPLE 20 A fabric of polyvinyl chloride fibres Thermovyl) is padded at room temperature (about 20C) with an aqueous dispersion which per litre contains 1 to 2 g of the compound of the formula 92) and l g of an addition product of about 35 mols of ethylene oxide to 1 mol of octadecyl alcohol, and is dried at about 70C. The dry material is subsequently subjected to a heat treatment for 3 minutes at 100C. The fabric of polyvinyl chloride fibres treated in this way has a substantially higher degree of whiteness than an untreated fabric of polyvinyl chloride fibres.

Similar results are achieved with the compounds of the formulae (43), (57), (61), (62), (67), (93), (94) or 97).

EXAMPLE 21 EXAMPLE 22 10,000 g of a polyamide in chip form, manufactured in a known manner from hexame'thylenediamine adipate, are mixed with 30 g of titanium dioxide (rutile modification) and 5 g of the compound of the formula 68) for 12 hours in a tumbler vessel.

The chips treated in this way are fused in a kettle heated to 300 to 310C by means of oil or diphenyl vapour, after displacing the atmospheric oxygen by steam, and the material is stirred for half an hour. The melt is thereafter extruded through a spinneret under a nitrogen pressure of 5 atmospheres gauge and the filament which has been spun in this way and cooled is wound up on spinning a spinning The filaments produced show an excellent brightening effect of good fastness to light.

If instead of a polyamide manufactured from hexamethylenediamine adipate apolyamide manufactured from e-caprolactam is used, simlarly good results are obtained.

Similar results are achieved with the compound of the formula (36), (37), (40), (45), (49), (52) to (57), (61), (67), (72), (86) or (91) to (97).

EXAMPLE 23 100 g of fibre grade polypropylene are intimately mixed with 0.8 g of the compound of the formula 68) and the mixture is fused at 280 to 290C whilst stirring. The melt is spun through customary spinnerets in accordance with melt spinning processes which are in themselves known, and the spun'material is stretched.

Strongly brightened polypropylene fibres are obtained.

Similar results are achieved with the compounds of the formulae (49), (57), (61), (62), (63) or (92) to 95).

EXAMPLE 24 v A 13 percent strength casting composition of acetylcellulose in acetone which contains relative to the dry weight of plastic 2 percent of anatase titanium dioxide) as a delustring agent and 0.04 percent of the compound of the formula 72), is cast. on a glass plate and spread by means of a metal rod to give a thin film. After drying, the film shows a substantially higher degree of whiteness than a film manufactured in the same way which does not contain an optical brightener.

Similar results are obtained on using the compounds ofthe formulae (43), (45 (56 (.57), (62), (63), (91 to (94) or (97).

EXAMPLE 25 100 parts of polystyrene and 0.1 part of the compound of the formula (93) are fused in a tube of 1 cm diameter for minutes at 210C, with exclusion of air. After cooling, an optically brightened polystyrene composition of good fastness to light are obtained.

Similar brightening effects are obtained when using a compound of the formulae (57), (62), (63), (67), (68), (91), (92) or (94).

EXAMPLE 26 EXAMPLE 27 1.5 g of a delustring agent, 1 g of titanium dioxide (rutile type) and 0.05 g of the compound of the formula 43) are stirred into a polyurethane coating com- 4 7 position of 133g of isocyanate-modified polyester,

EXAMPLE 29 7 g of anatase (TiO followed by 350 g of polyacrylonitrile polymer (=PAC) in powder form are added to 1,400 ml of dimethylformamide; the mixture is converted into a viscous mass by means of a high speed stirrer.

5 mg of the compound of the formula 56) are added to 50 g of this 20 percent strength PAC solution. This mixture is homogenised by stirring and is then left to stand for 1 hour in order to allow the air bubbles produced to diffuse out.

Thereafter the composition is cast on a glass plate and spread by means of a metal rod to give a uniform film.

The PAC film is then dried in a drying cabinet for approx. 15 minutes at 50C with ventilation air extraction) and then at room temperature with slight ventilation. The PAC film can then be removed easily from the glass plate. It has a substantially higher degree of whiteness than the film manufactured in the same way which does not contain the optical brightener.

Similar results are obtained when using the compounds of the formulae (37), (43), (45), (53), (54), (58), (62), (72), (86), (91), (92), (94), (96) or (97).

1 claim: 1. A bis-stilbene compound of the formula X1 X2 W Q R 0 0 R2 a a g 26.7 g of ethyl acetate, 2 g of a reaction accelerator and EXAMPLE 28 An intimate mixture of 100 parts of polyvinyl chloride, 3 parts of stabiliser (Advastat ED 100: Ba/Cd complex), 2 parts of titanium dioxide, 59 parts of dioctyl phthalate and 0.01 to 0.2 part of the compound of the formula (43) are milled on a calender at 150 to 155C to give a sheet. The opaque polyvinyl chloride sheet thus obtained has a substantially higher degree of whiteness than a sheet which does not contain the optical brightener.

The compounds of the formulae 45), (49), 53), (56) to (58), (61) to (65), (67), (68), (72), (91) to 97) give similar effects.

where R, and R each independently is (CH ),,COOM where n is an integer from 1 to 3 and M is hydrogen, sodium potassium, ammonium or alkyl of 1 to 8 carbon atoms,

a is hydrogen, halogen, or alkyl or alkoxy of one to four carbon atoms,

X, and X each independently is hydrogen, alkoxy of one to four carbon atoms, halogen, alkenyl of three to four carbon atoms or alkyl of one to four carbon atoms,

Y, and Y each independently is hydrogen, halogen, alkenyl of three to four carbon atoms, or alkyl of one to four carbon atoms,

and provided that the para-positions are free of alkoxy groups or groups R,O and R 0.

2. A bis-stilbene compound according to claim 1 where a is hydrogen.

3. A bis-stilbene compound according to claim 2 in which X,, X Y, and Y each is hydrogen, and

R, and R each is CH,),,COOM

where n is an integer from 1 to 3 and M is hydrogen, sodium, potassium, ammonium or alkyl of one to eight carbon atoms. 

1. A BIS-STILBENE COMPOUND OF THE FORMULA
 2. A bis-stilbene compound according to claim 1 where a is hydrogen.
 3. A bis-stilbene compound according to claim 2 in which X1, X2, Y1 and Y2 each is hydrogen, and R1 and R2 each is -(CH2)nCOOM where n is an integer from 1 to 3 and M is hydrogen, sodium, potassium, ammonium or alkyl of one to eight carbon atoms. 